x11-libs/libxshmfence: new package, add 1.3.2-r1

Signed-off-by: James Calligeros <[email protected]>

x11-libs/libxshmfence/Manifest

@@ -0,0 +1 @@
+DIST libxshmfence-1.3.2.tar.xz 259024 BLAKE2B 2f0ef0767fbb29349acf43b4cb4d7177956c06c389f0443db06e398c4e0f3b424432ce6fe8946d70fdd59b9446c53bf2f1ee126df4d41b3065f1e94438facecf SHA512 e20a6827e370726cf50489a69f4a52b897f1c44e3eba8c72a4e626b08724e877d090770b8016765736d887d5d5eaba1fda9c29066e62d259b4d1e2064bc1626c

x11-libs/libxshmfence/files/libxshmfence-1.3.2-memfd-envvar.patch

@@ -0,0 +1,53 @@
+From 3aaf46a2742d1698f3a4399b2bb2f855c0b904fe Mon Sep 17 00:00:00 2001
+From: Asahi Lina <[email protected]>
+Date: Tue, 22 Oct 2024 22:28:19 +0900
+Subject: [PATCH] alloc: Allow disabling memfd usage at runtime with
+ XSHMFENCE_NO_MEMFD=1
+
+For thin VMs used for compatibility reasons, it is desirable to directly
+proxy the X11 protocol between an application running in a VM and an X
+server running on the host. We can proxy futex wakeups with some watcher
+code, but we need the futex memory itself to be shared. This works when
+/dev/shm is mounted with virtiofs with DAX, but cannot work for memfds.
+
+Add a XSHMFENCE_NO_MEMFD environment variable that, when set, disables
+the memfd codepath and falls back to /dev/shm.
+
+Signed-off-by: Asahi Lina <[email protected]>
+Part-of: <https://gitlab.freedesktop.org/xorg/lib/libxshmfence/-/merge_requests/9>
+---
+ src/xshmfence_alloc.c | 13 +++++++++++--
+ 1 file changed, 11 insertions(+), 2 deletions(-)
+
+diff --git a/src/xshmfence_alloc.c b/src/xshmfence_alloc.c
+index 932adb9..77f968c 100644
+--- a/src/xshmfence_alloc.c
++++ b/src/xshmfence_alloc.c
+@@ -69,13 +69,22 @@ int
+ xshmfence_alloc_shm(void)
+ {
+ 	char	template[] = SHMDIR "/shmfd-XXXXXX";
+-	int	fd;
++	int	fd = -1;
+ #ifndef HAVE_MKOSTEMP
+ 	int	flags;
+ #endif
+
+ #if HAVE_MEMFD_CREATE
+-	fd = memfd_create("xshmfence", MFD_CLOEXEC|MFD_ALLOW_SEALING);
++	static int disable_memfd = -1;
++
++	if (disable_memfd == -1) {
++		const char *val = getenv("XSHMFENCE_NO_MEMFD");
++		disable_memfd = val ? !!atoi(val) : 0;
++	}
++
++	if (disable_memfd <= 0)
++		fd = memfd_create("xshmfence", MFD_CLOEXEC|MFD_ALLOW_SEALING);
++
+ 	if (fd < 0)
+ #endif
+ #ifdef SHM_ANON
+-- 
+GitLab
+

x11-libs/libxshmfence/libxshmfence-1.3.2-r1.ebuild

@@ -0,0 +1,18 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+XORG_MULTILIB=yes
+XORG_TARBALL_SUFFIX="xz"
+inherit xorg-3
+
+DESCRIPTION="Shared memory fences using futexes"
+
+KEYWORDS="~arm64"
+
+DEPEND="x11-base/xorg-proto"
+
+PATCHES="
+	${FILESDIR}/${P}-memfd-envvar.patch
+"

x11-libs/libxshmfence/metadata.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+  <maintainer type="project">
+    <email>[email protected]</email>
+    <name>X11</name>
+  </maintainer>
+  <upstream>
+    <remote-id type="freedesktop-gitlab">xorg/lib/libxshmfence</remote-id>
+  </upstream>
+</pkgmetadata>